Grass mowing machines with reel mower cutting units are used on golf courses and other turf areas that require grass to be cut very accurately. The cutting units are typically rolled across the surface of the ground by a powered vehicle. The cutting units include a generally cylindrical reel with a plurality of blades that rotate in close proximity to a stationary bedknife fixed with the frame of the cutting unit. Grass is cut by a shearing action between the bedknife and the rotation blades of the reel.
Attachments on reel mower cutting units may be used to improve the quality of the cut, performance, and other turf grooming features. The attachments, such as conditioners, roller power brushes, or turf grooming brushes, may be rotated by auxiliary drives mounted to the reel mower cutting unit and powered by the shaft of the cutting reel. An auxiliary drive may transmit rotational power from the cutting reel shaft to the attachment through a set of gears or a belt on a pair of sprockets or pulleys.
A conditioner, for example, is an attachment used for finer grooming of turf areas such as putting greens, by reducing thatch, slicing stolons, controlling grain, and deflecting material away from the reel and bedknife. A conditioner may stand the grass up for an even, clean cut and truer putting green surface. A typical conditioner includes a number of (for example, 72) closely spaced vertical blades mounted on a horizontal shaft adjacent one of the rollers. The blades may have a diameter of between about 40 and 80 mm, and preferably between about 50 and 65 mm. A conditioner may be counter-rotated to the direction of travel of the cutting unit. An auxiliary drive, sometimes referred to as a conditioner drive, transmits rotational power from the cutting reel shaft to the conditioner. For example, a conditioner drive may include a set of gears that rotate the conditioner at speeds of about 2000 rpm.
A roller power brush is an attachment used to prevent accumulation of grass clippings and other debris on a roller supporting a reel mower cutting unit, so that the cutting unit can maintain a consistent effective height of cut. The brush may be rotatably mounted to the cutting unit above and adjacent the rear roller, for example. The brush may include radially extending bristles on a brush shaft. The brush may be rotated by an auxiliary drive opposite to the direction of travel of the reel mower cutting unit. For example, the auxiliary drive may be a belt drive that transmits rotational power from the cutting reel shaft to the brush through a belt on sprockets that turns the brush at a desired rotational speed.
It is desirable to provide and maintain proper tension of a belt in an auxiliary drive for a reel mower cutting unit. The belt in an auxiliary drive may stretch due to wear and adverse operating conditions. Conventional auxiliary drives lack any belt tightening mechanism, or tightening the belt is very cumbersome. When the belt is tightened, it also is desirable to allow moving the attachment to different settings, while maintaining positive centering of the auxiliary drive output shaft with the attachment.